Re: [PATCH] arm64: vdso32: Fix '--prefix=' value for newer versions of clang

From: Sedat Dilek <sedat.dilek@gmail.com>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Clang-Built-Linux ML <clang-built-linux@googlegroups.com>,
	stable@vger.kernel.org,
	Masahiro Yamada <yamada.masahiro@socionext.com>
Subject: Re: [PATCH] arm64: vdso32: Fix '--prefix=' value for newer versions of clang
Date: Thu, 23 Jul 2020 06:45:07 +0200	[thread overview]
Message-ID: <CA+icZUVUSnC9F5RKzRLV50CU8SwortEFGH5f2LHTu=UQx8dT8g@mail.gmail.com> (raw)
In-Reply-To: <20200723041509.400450-1-natechancellor@gmail.com>

On Thu, Jul 23, 2020 at 6:15 AM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> Newer versions of clang only look for $(COMPAT_GCC_TOOLCHAIN_DIR)as [1],
> rather than $(COMPAT_GCC_TOOLCHAIN_DIR)$(CROSS_COMPILE_COMPAT)as,
> resulting in the following build error:
>
> $ make -skj"$(nproc)" ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- \
> CROSS_COMPILE_COMPAT=arm-linux-gnueabi- LLVM=1 O=out/aarch64 distclean \
> defconfig arch/arm64/kernel/vdso32/
> ...
> /home/nathan/cbl/toolchains/llvm-binutils/bin/as: unrecognized option '-EL'
> clang-12: error: assembler command failed with exit code 1 (use -v to see invocation)
> make[3]: *** [arch/arm64/kernel/vdso32/Makefile:181: arch/arm64/kernel/vdso32/note.o] Error 1
> ...
>
> Adding the value of CROSS_COMPILE_COMPAT (adding notdir to account for a
> full path for CROSS_COMPILE_COMPAT) fixes this issue, which matches the
> solution done for the main Makefile [2].
>

[ CC Masahiro ]

Masahiro added a slightly adapted version of [2] in <kbuild.git#fixes>.
Shall this go through kbuild subsystem or folded into [1]?

- Sedat -

[1] https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git/commit/?h=fixes&id=ca9b31f6bb9c6aa9b4e5f0792f39a97bbffb8c51

> [1]: https://github.com/llvm/llvm-project/commit/3452a0d8c17f7166f479706b293caf6ac76ffd90
> [2]: https://lore.kernel.org/lkml/20200721173125.1273884-1-maskray@google.com/
>
> Cc: stable@vger.kernel.org
> Link: https://github.com/ClangBuiltLinux/linux/issues/1099
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>  arch/arm64/kernel/vdso32/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
> index d88148bef6b0..5139a5f19256 100644
> --- a/arch/arm64/kernel/vdso32/Makefile
> +++ b/arch/arm64/kernel/vdso32/Makefile
> @@ -14,7 +14,7 @@ COMPAT_GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE_COMPAT)elfedit))
>  COMPAT_GCC_TOOLCHAIN := $(realpath $(COMPAT_GCC_TOOLCHAIN_DIR)/..)
>
>  CC_COMPAT_CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%))
> -CC_COMPAT_CLANG_FLAGS += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR)
> +CC_COMPAT_CLANG_FLAGS += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE_COMPAT))
>  CC_COMPAT_CLANG_FLAGS += -no-integrated-as -Qunused-arguments
>  ifneq ($(COMPAT_GCC_TOOLCHAIN),)
>  CC_COMPAT_CLANG_FLAGS += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN)
>
> base-commit: d15be546031cf65a0fc34879beca02fd90fe7ac7
> --
> 2.28.0.rc1
>
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